Cayuga Lake Modeling Project Major Findings and Management Implications April 2017 Photo: Bill Hecht
Permit requirements and deliverables REQUIREMENT DATE (S) COMPLIANCE MODELING PROJECT • Workplan and QAPP- monitoring March 2013 • Workplan and QAPP- modeling Dec. 2014 • Final Report and model hand-off Dec. 2016 OUTFALL REDESIGN • Workplan approval May 2014 • Progress reports Jan. 2015, Sept. 2015, May 2016 • Final Report Nov. 2016 BIOMONITORING • Workplan Feb .2014 • Permit Modification Final report April 2015 CAMPUS BMPS • Feb. 2014, 2015, 2016, 2017 Annual Reports SUPPORT DEC WITH OUTREACH • Technical meetings May 2014, Nov. 2014, Oct. 2015 • Stakeholder meetings Multiple (30 +) • Public meetings (pre-TMDL) Dec. 2013, July 2014, March 2016 April 2017 2
Cayuga Lake Modeling Project (CLMP) Overview • Investigated phosphorus (P) inputs and phytoplankton growth • Developed mathematical models of the lake and watershed • Provided NYSDEC with tools for a science-based Photos, illustrations, graphics here. approach to lake management April 2017 3
Project Overseen and Directed by NYSDEC • Workplan and QAPP • Technical meetings to review progress and model assumptions – EPA convened Model Evaluation Group – DEC convened Technical Advisory Committee • Presentations to watershed stakeholder groups – Regular updates to the WRC Monitoring Partnership • Open public meetings • 20+ technical peer-reviewed publications April 2017 4
Opportunity to Advance Science and Policy • Engage world-class researchers to improve understanding of Cayuga Lake • Integrate science into policy decisions • Apply an ecosystem-based management approach to examine human impacts on natural systems, including water, air, and lands April 2017 5
Key Questions 1- Class B • What are the point and nonpoint sources of TP? 2- Class A(T) Why is TP elevated in Segment 4? • How much of measured TP supports phytoplankton 3- Class AA (T) growth? • How does water movement affect distribution of TP and phytoplankton? How do the answers to these key questions inform our understanding of impacts of Cornell’s Lake Source Cooling facility? 4- Class A 6 April 2017
3 Integrated Models to Answer the Questions • Watershed Model (SWAT) Quantifies relationship of land use, soils, slopes, and management practices on nutrient & sediment export • Lake Water Quality Model (CL-W2) Projects the impact of point and nonpoint sources on lake nutrients, algae, clarity, and other metrics • Hydrodynamic Model (Si3D) Simulates water movement in the lake (three dimensional) April 2017 7
What did we learn from the models? Photo: Bill Hecht April 2017 8
What are the point and nonpoint sources of TP? Why is TP elevated in Segment 4? Site-specific investigations o Lake, tributary streams, and point sources were monitored (capturing storm events) Model Integration o Watershed model identifies P contributing areas and practices o Lake water quality model tracks P fractions and predicts phytoplankton growth Findings o Tributaries contribute > 97% TP to lake o Elevated TP on the shelf is associated with sediment from runoff during storm events April 2017 9
How much of measured TP supports phytoplankton? Site-specific Investigations o P bioavailability testing of streams, point sources, LSC return flow, Cayuga Lake Model Integration o Lake water quality model explicitly tracks P fractions with respect to their algal growth potential o Watershed model tracks dissolved and particulate P Findings o Occasional elevated TP on shelf after storm events, low bioavailability of P sorbed to these clay-sized particles ~3% o Tributary streams contribute ~95% of Bioavailable P to the lake 10 April 2017
Total P and Chlorophyll-a, 1998- 2013, 2016 30 Summer Average TP, ug/L 25 20 15 10 5 Shelf Main Lake 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2016 12 Chlorophyll-a, ug/L 10 Summer Average 8 6 4 2 Shelf Main Lake 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2016 April 2017 11
How does water movement affect distribution of TP and phytoplankton? Site-specific Investigations o Instrumentation to record lake current velocity & temperature o Collaboration with US Naval Research Observatory for fly-over during intensive grid study (August 2014) Model Integration o Si3D model was applied to define LSC mixing zone and shelf dynamics o Lake water quality model was applied to examine the impact of shelf water residence time on phytoplankton Findings LSC induced flow is 10X larger than LSC discharge o o Outfall relocation increases shelf residence time by 67%, with associated increase in TP, chlorophyll, & turbidity 12 April 2017
Mixing processes prevent development of higher phytoplankton biomass on the shelf Wind-induced flow on and off shelf “Flushing rate of the shelf Water exchange from mixing is rapid with main lake relative to phytoplankton 10X LSC induced flow growth rates” on and off shelf (Effler et al. 2010; Gelda et al. 2015a) SHELF: Cayuga Lake Lake Source Cooling return flow Segment 4 Photos, illustrations, graphics here. 1.8 miles 965 acres ~ 3,146 mg Large southern tributaries Fall Creek, Cayuga Inlet April 2017 13
Implications for the LSC SPDES permit renewal April 2017 14
Projected TP and Chlorophyll-a, With and Without LSC Discharge to Segment 4 30 Total Phosphorus Chlorophyll-a Summer Average TP and 25 Chlorophyll-a, ug/L 24.1 23.3 20 15 10 11.6 11.6 5 5.7 5.6 4.8 4.8 0 Southern Shelf Main Lake Southern Shelf Main Lake Current Conditions No Lake Source Cooling Source: UFI, Dec. 2016. Phase 2 Final Report. Table 7-17, page 7-88. April 2017 15
Adverse Impacts of Extending the LSC Outfall • Environmental – No water quality benefit to shelf or main lake; may slightly exacerbate impairment of Segment 4 for TP and silt/sediment • Energy & Climate – Increased energy use from pumping diminishes the benefits of LSC – Retreat from University and NYS commitments to climate action • Fiscal – Expensive, costs borne by NYS-supported colleges and the University April 2017 16
Permitting Challenges • Currently, need to restrict LSC during high demand periods to meet interim TP limit of 6.4 ppd • Final TP limit 4.8 ppd would severely impact University operations • Outfall extension has adverse impacts on air & water quality, plus state and University finances • Construction of new chillers to replace LSC capacity would be even more costly and environmentally damaging April 2017 17
Looking Ahead • The CLMP illustrates Ecosystem-based Management approach to water resources – State-of-the-art modeling – Develop “place - based” information – Active stakeholder engagement – Recognition that humans are part of the ecosystem; manage for multiple uses; and consider impacts on land, air, and climate as well as water • Opportunity for NYS to continue leadership on climate actions April 2017 18
All Reports, Presentations, Technical Papers and Data are on the Cayuga Lake Modeling Project Webpage www.cayugalakemodelingproject.cornell.edu April 2017 19
Questions and Discussion Thank You April 2017 20
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Longitudinal-Vertical Grid - Cayuga Lake Distance from downstream boundary (railroad bridge; km) 60 55 50 45 40 35 30 25 20 15 10 5 0 120 110 LSC discharge 100 discharge 90 LSC 80 70 Cayuga-AES power Cayuga-AES power plant Elevation (m) 60 intake plant intake 50 LSC 40 LSC intake intake 30 20 10 48 segments 0 132 layers -10 3720 cells -20 23
4 Watershed Model Soil Water Assessment Tool (SWAT) Developed by USDA-ARS, Texas A&M Widely used in TMDL-type projects Simulates dissolved & particulate P Adaptable to local conditions Flexible management input Google Images April 2017 24
Land Use/Land Cover Affect Phosphorus Export Lyon, Walter, et al. 2006. JAWRA. 42(3): 793-804 • Streams draining % Forest 100% 0% 0.30 agricultural areas have Total P (mg/L) higher phosphorus concentrations 0.00 Photos, illustrations, graphics here. 0% 100% % Agriculture April 2017 25
Objectives of the Watershed Model • Estimate phosphorus loads from the watershed – Inform lake model inputs • Provide a tool to test management (“what - if”) scenarios April 2017 26
Watershed Modeling Tool • Current conditions • Hindcast: What were sediment and phosphorus loads pre-settlement (1700s)? • Management: – Turn off individual sources – Implement agricultural Best Management Practices • Change the timing of manure applications ~ avoid forecasted rain • Change the placement of manure ~ buffers around concentrated flow paths • Other recommended practices ~ cover crops, swales • Forecast: Potential changes in a future climate April 2017 27
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